Medium Anti-Knight Sudoku

Cells a chess knight's move apart cannot share the same digit. A global constraint that shapes every row and column.

Easy Medium Hard Expert

Anti-Knight Sudoku at medium difficulty. Knight's-move chains cross box boundaries — track them carefully alongside standard row, column, and box logic.

1
2
3
8
6
1
8
3
9
9
8
4
1
1
6
4
2
7
1
9
6
8
6
2
3
7
1
2
5
8
9
3
Mistakes
0/3
Score
-
Time
00:00
Try Hard Anti-Knight Sudoku →
Progress0%
♞ Knight's move constraint active

What is Anti-Knight Sudoku?

Difficulty
★★★☆☆
3/5
Constraint Type
Anti-Constraints
Typical Givens
20–26
Avg. Solve (Medium)
12 min

Solving Techniques for Medium Level

Technique Description Level
Knight-Zone Mapping For each cell, mark all potential knight-move destinations (up to 8 cells). None may share the same digit as the source cell. Beginner
Corner and Edge Advantage Corner cells have only 2 knight-move neighbours; edge cells have at most 4. These restricted zones are easiest to resolve first. Beginner
Knight Chains Placing a digit can eliminate it from a chain of knight-move positions that span diagonally across the grid. Intermediate

Master these, then take on Hard Anti-Knight Sudoku to learn Advanced techniques.

Techniques to Master at Medium

  • Hidden Singles technique — A digit's knight-move shadow reaches into boxes its row and column never touch — recount each box after mapping the L-shaped eliminations and hidden singles appear across the grid.
  • Obvious Pairs technique — Two cells a knight's move apart can never share a digit, so a candidate pair spanning such cells silently breaks — prune these before trusting any pair elimination.

Average Solve Time by Difficulty

Easy
5 min
Medium
12 min
Hard
24 min
Expert
45 min
Want a full walkthrough of rules, strategies, and solving steps? How to Play Anti-Knight Sudoku →

Related Variants

Anti-King Sudoku

The shorter-range chess rule — repeats forbidden among all eight touching cells rather than across L-shaped leaps.

Anti-Consecutive Sudoku

Trades geometric reach for value logic: orthogonal neighbours may never hold consecutive digits.

Non-Consecutive Sudoku

Same constraint family — a global unmarked rule whose eliminations cascade after every placement.

Frequently Asked Questions — Medium Anti-Knight Sudoku

What techniques are most useful for medium Anti-Knight Sudoku?
At medium difficulty, combine hidden singles and naked pairs with knight's-move elimination chains. The knight's constraint is especially powerful when a digit is nearly placed in a row or column — the knight's-move restriction across rows often limits the digit to a single cell.
What is a knight's-move elimination chain?
A knight's-move elimination chain occurs when placing digit X in cell A eliminates X from a knight's-move neighbor B, which forces another digit into B, which then eliminates further candidates via the knight's constraint from B's own knight's-move neighbors. Medium puzzles regularly require chains of 3–5 steps.
How does the knight's constraint affect box solving?
Within a 3×3 box, the knight's constraint adds long-range restrictions. A digit placed near the corner of a box can eliminate that digit from cells two rows or columns away in adjacent boxes. This cross-box elimination is often what unlocks medium puzzles.
Should I use pencil marks for medium Anti-Knight Sudoku?
Yes. Initialize your candidate lists for each cell using row, column, and box constraints, then also eliminate any digit that appears in a knight's-move neighbor. This extended initialization often reveals more hidden singles than the standard approach alone.
How long does a medium Anti-Knight Sudoku take?
Most players finish a medium Anti-Knight Sudoku in 12–25 minutes. Players who forget to apply the knight's constraint consistently will take longer, as they'll miss the extra eliminations that make the puzzle flow.

More questions? See the full Anti-Knight Sudoku guide.